Squid-spiration Guides New Camo

The squid is the unlikely guru behind the "invisibility stickers" project now underway at the University of California-Irvine.

Soldiers in camouflage-pattern uniforms "blend into foliage during the day, but under low light and at night, they're still vulnerable to infrared detection," says UCI's Alon Gorodetsky, Ph.D.Adjusting the film's thickness can create different colors.

Images and video: American Chemical Society / Henrik Steenfeldt

The technology could even be used to avoid infrared detection, which is widely used in military and industrial applications, developers say.

Night-time Vulnerability

"Soldiers wear uniforms with the familiar green and brown camouflage patterns to blend into foliage during the day, but under low light and at night, they're still vulnerable to infrared detection," UCI's Alon Gorodetsky, Ph.D., explains in a research announcement by the American Chemical Society.

"We've developed stickers for use as a thin, flexible layer of camo with the potential to take on a pattern that will better match the soldiers' infrared reflectance to their background and hide them from active infrared visualization."

The research was presented March 23 at ACS's 249th National Meeting & Exposition in Denver. ACS is the world's largest scientific society.

Super Skin

The stickers' secret ingredient is a protein called reflectin. Layers of the protein are found in cells called iridocytes on the squid's skin. Using a "biochemical cascade," the squid can change the thickness and spacing of the protein layers, changing how the cells reflect light and show color.

Layers of a protein called reflectin, activated by a biochemical cascade, help the squid avoid detection. University of California-Irvine researchers want to do the same for soldiers and security personnel.

Unwilling to slaughter squid in the name of his invention, Gorodetsky and his group developed a way to produce reflectin from bacteria in the lab and then coated a hard substrate with the protein. To trigger the light-reflecting changes, the team initially tried acetic acid vapors,"essentially exposing it to concentrated vinegar."

Effective but impractical for field use, the vinegar vapors were backburnered in favor of a reflective film or tape, which can stick to uniforms and other surfaces. The trigger in this iteration is mechanical—stretching.

The team is "continuing to tweak the materials" to work at mid- and far-infrared wavelengths, ACS said.

Stealth Applications

One day, Gorodetsky hopes, soldiers and security personnel can carry a roll of invisibility tape into combat.

With the tape capable of adhering to a variety of surfaces and its reflectance adjustable, "we can endow common objects with any shape or form factor with tunable camouflage capabilities," the team writes.

The project takes "a key step toward the development of wearable biomimetic color and shapeshifting technologies for stealth applications," it says.